Long-time study of fibre-reinforced concrete, i.e. a composite material with a cementitious matrix, whose structure is hardened by usually randomly distributed fibres (steel ones in the most frequent case), demonstrates good mechanical and other technical properties, which makes possible its utilization in bearing structures. This stimulates the development of methods, non-destructive or low-invasive if possible, for the analysis of its structure, which determines crucial mechanical properties, e.g. fracture resistance under tensile loads. This article, coming from research activities of the Faculty of Civil Engineering at Brno University o Technology, brings an overview of available methods, namely direct methods coming from image processing and indirect ones utilizing measurements of electromagnetic quantities.
1 comment, 27.03.2017 11:54
The article explains the differences between the invention patents and utility model from the perspective of Czech legislation. Also highlights the confusion individual categories and purposeful fraud by producers and sellers of equipment.
1 comment, 08.03.2017 07:44
The natural radioactivity lives mankind throughout its development. The effects of radiation to some extent they can influence the evolutionary history of life on Earth. It is therefore important to determine what values the natural radioactivity would reach different locations of the world.
Floor area in living spaces with slanting ceilings has an ambiguous interpretion in czech national regulations. It has an effect on a building approval process and this article describes how to determine this area in both architecture and civil enginnering.
1 comment, 21.06.2016 11:21
The study is focused on evaluation of titanium dioxide nanoparticles (N-TiO2) impact on photocatalytic properties of concrete surface. Specimens made from ordinary white cement with no TiO2 particles, specimens made from commercially available photocatalytic cement and specimens made from white cement covered with polyvinyl alcohol (PVA) nanotextile containing N-TiO2 were compared with respect to their ability to decompose rhodamine B dye when exposed to direct UV radiation. PVA nanotextile was prepared by electrospinning method. The solution exploiting the nanotextile was not found to be prospective in this phase of the research. However, the method of preparation of enriched nanotextiles as well as their application on the surface of concrete elements was tried and can be adjusted for different purposes.
The article describes use of Miscanthus sinensis for a manufacturing of pulp. Miscanthus sinensis is a perennial plant, its cultivating is easy and it can be used for various purposes.
In the first phase of the pulp preparation from Miscanthus, a laboratory preparation of pulp was done at the University of Pardubice in total amount of 6 individual batches. In the second phase a selected laboratory batch was prepared in a pilot production process and ca. 2000 g of pulp in total was generated for further tests.
Mechanical properties and also other properties typical for pulp were determined on prepared samples. The produced pulp was used in the next step for a preparation of fibre-cement boards. Their basic physico-mechanical parameters were also determined.
After evaluation of all data that we have, production of 500 kg of pulp was done. Then the pulp was used to produce fibre-cement boards in a mass production.
In this research study we analyzed air permeation rate of oriented strand boards, OSB/3 and OSB/4 according to the ČSN EN 12114. OSB boards were manufactured in accordance with the ČSN EN 300 in the Czech Republic. We evaluated the influence of the board thickness (for the most used board thickness 12 and 18 mm) and the influence of the board type (OSB/3 and OSB/4) on air permeation rate values. We have proved that the groups of OSB/3 samples show lower resistance to air permeability than OSB/4. Furthermore 18 mm thick samples at both board types show higher resistance to air permeability than 12 mm thick samples.
3 comments, last 29.01.2016 12:48
Transparency and also smooth, glossy and reflective glass surface give special importance of this material in the contemporary architecture. Connections between two glass elements or glass pane and other part from a different material are very important issue for structural applications of glass. Moreover, there are many types of hybrid structures that combine glass and different materials to achieve safe failure behaviour and high degree of transparency at the same time. Connection of brittle glass and reinforcing material is an essential part of these structures, where composite action between two parts is beneficially ensured by a glued joint. Experimental determination of mechanical characteristics of various adhesives applied in planar connections under shear loading is a main topic of current paper.
Concrete exposed to high temperature considerably changes its properties down to total destruction. The paper describes renovation of concrete floor damaged by a fire of a factory building. Individual steps of determination of damage of concrete floor structures caused by high temperatures are described. Structure of damaged floor was technically analyzed, redevelopment was designed and renovation works were carried out.
This article deals about tropical hardwood species used for commercial purposes. These kinds of wood have more advantages like better natural durability against bio-degradation caused by high amount of extractives and good mechanical and physical properties. But their using is also connected with some questions – ecological and economical aspects and stability of supposed properties for each delivery. Not solved problem is protection against weathering and mainly decreasing of colour changes of tropical wood surfaces in the exterior till now.
The article describes floor surfaces and form of their determination in construction and other fields, such as services, real estate, valuation, facility management and more. In Europe, each country has a different technical standard. This means that when we are determining the type of floor area for buildings with these technical standards, we can conclude that they differ by up to 30 %. Therefore, we chose a sample idea of building on which we symbolized each floor type. We tried to make clear, which constructions and types of floor are creditable and which are not. To demonstrate the importance of correct identification of floor surface we give an example calculation of cleaning services where savings could be seen in the correct determination of the floor surface.
These series of articles focuses on the issue in terms of microbial purity level in internal environment, ventilation and heating systems of residential buildings. The issue relative to its scope is divided into several parts, following: Microbial microclimate of buildings and its limits, Collection and cultivation of samples from the family houses, Rating of family houses, Microbial microclimate in educational establishments, Heating surfaces and microbial environment.
The aim of this set of articles is to present methods and results of the subsequent mapping of microbial contamination of the interior of buildings to technical specialists and readers. The questionnaire survey will enable us to evaluate an impact of the MEP systems for indoor environmental quality, especially its microbial component. Those articles will present the work and the results processed in the framework of the specific research Brno University of Technology, Faculty of Civil Engineering, Institute of technical equipment of buildings under project FAST-S-15-2620.
Analysis of the appropriateness of using osb boards as the main airtightening layer in timber construction25.5.2015 | Ing. et Ing. Jan Dvořák, VUT v Brně, Fakulta stavební, Ústav technologie, mechanizace a řízení staveb
This article deals with the assessment of applicability of OSB boards as the main airtightening layer. Different material thicknesses and various kinds of surface modifications of boards were tested. Measurements were performed with blower-door test in an airtight chamber, which is located in the experimental wooden structure EXDR 1. The article describes a procedure of the experiment and its results.
The article presents a technological procedure and possibilities for surface treatment of different materials by using compact parts of CO2dry ice. A purifying medium is accelerated in the nozzle of the SDI Select 60 device by compressed air stream to a supersonic speed, and so it reaches high kinetic energy. The impact of CO2 at the temperature −78.8 °C rapidly cools down the surface; dirtiness becomes brittle and loses its base adhesion, causing temperature shock. Simultaneously with this temperature effect, dry ice intensively sublimates, increases its volume and removes, at high inner tension, the impaired surface of dirtiness without any formation of abrasion waste. The device is applicable to the removal of contamination from elements which cannot be saturated with water or when it is necessary to modify elements with no need to dismantle them. The report introduces the technology when removing contamination on the surface of wooden construction elements, artefacts and stone statues, as well as when forming a relief on the native wooden surface and at a surface treatment before the application of paint, or fungicidal and insecticidal agents.
Czech version of the renowned handbook TCNA contains guidelines for the design and execution of tiles made of ceramic, glass and stone. Contains a description of 155 standardized methods, guidelines for designing Movement Joint of Floors, Environmetal Classification. LEED and other information necessary for the proper design and execution of tiles. Guide creates a quality system. It was registered with the Chamber of Commerce as rules of practice. The manual is intended for designers, architects, craftsmen, construction management, investors, students, etc.
Loggias and balconies are external structures designed for recreation and other activities, which increase the value and the surface of the property. They are positioned as part of the cladding of the building. Actually, these structures are perhaps the most exposed components of a building's cladding, and for this reason, the most degraded. This is why the repairing of these structures should certainly be included in any comprehensive renovation of a building, even though it might not have any financial effect for the owners and tenants, unlike, for example, changing fillings or additional insulation.
Railings are a safety feature in buildings. They should prevent the fall of people. Their requirements are not only architectural and aesthetic, but also of mechanical resistance and stability. The current designs for the construction of railings include their anchoring to adjacent structures, which have the same requirements as the very structure of the railings. The tests on heat pumps are connected to an article on the tests of solar collectors. The basic operating principles of a heat pump is that it gathers heat from the surrounding environment and then transfers it to a higher temperature level and supplies to according the whether it will be used for heating or hot water. The advantage over collectors is that it works even if the sun is not shining.
5 comments, last 24.10.2013 21:25
The paper compares the floor flatness measurement methodology and requirements defined in the Czech standard ČSN 74 4505 Podlahy, společná ustanovení and the German DIN 18202 Toleranzen im Hochbau - Bauwerke. There is an example of the floor assessed by both procedures, shown in the end of the paper.
1 comment, 16.05.2016 11:27
Prague Building Regulations – The Analysis of the Fundamental Principles of Territorial Requirements20.10.2014 | Ing. arch. Marek Janatka, Ph.D., Katedra urbanismu a územního plánování Fakulta stavební ČVUT v Praze
Prague building regulations currently represent debated and controversial topic among both professionals and the public. This is a new concept of law to which they are greatly implemented basic knowledge of urban theory and practice. The article summarizes the basic principles of the new regulation in the field of territorial requirements.
An overview of the development and standard types of the prefabricated wooden houses, their basic structural materials, basic mechanical timber joints, design practice for loads effects and requirements for structural elements is presented in the five-part series. In the second part basic structural materials are dealt with.